1. Field of the Invention
This invention relates generally to communications networks. More particularly, it relates to the communication between a mobile (i.e., wireless) device and an application server via a short message service center (SMSC) and the Internet.
2. Background of Related Art
Wireless communication services are in increasing demand in response to a society which is becoming increasingly mobile. Traditionally, wireless communication services include voice cellular phone and paging services in which a user can make a telephone call or send/receive a page including a numeric message indicating a telephone number over a wireless network. More recently, paging services have been expanded to offer alphanumeric paging, which allows a short text based message to be sent to and displayed at a handheld pager.
However, voice cellular telephone and the paging services each require an intended subscriber to be on-line or active to receive a telephone call or transmitted paging message. In other words, these services do not typically offer the capability of storing the messages for a temporarily unavailable subscriber.
In the early 1990s, as a result of the growing popularity of digital wireless technology, a standard for digital wireless networks was introduced in Europe. That standard, now known as the global standard for mobiles (GSM), included a service called short messaging service (SMS). An SMS allows transmission of short messages, typically up to 160 characters, to and from communication devices, e.g., cellular telephone handsets, telephones or computers with appropriate modems. In North America, the SMS is currently implemented on digital wireless/mobile networks, such as a PCS network based on the GSM standard, code division multiple access (CDMA) and/or time division multiple access (TDMA) methods. Short message services are gaining in popularity, particularly in the United States.
Short message services are advantageous over text based paging services because of the capability of bi-directional communication. Such bi-directional communication allows, for example, notification to the originating device of the success or failure of the short message delivery.
Each SMS network typically includes a short message service center (SMSC) which acts as a store-and-forward mechanism providing guaranteed delivery of short messages to a subscriber, even if the subscriber is inactive when the message was transmitted, by delivering the short messages once the subscriber becomes active. Delivery of all short messages is guaranteed regardless of whether or not the intended subscriber is “on-line” because the transmitted short message is stored within the SMS network and delivered to the intended subscriber from their assigned SMSC when the subscriber becomes available.
A variety of services have been introduced using SMS networks including, for example, integrated electronic mail and fax, integrated paging, interactive banking, and information services such as stock quotes and airline schedule delivery.
In operation, an SMSC receives a short message from any source intended to be delivered to a particular subscriber. When the intended subscriber is not available because, for example, it is turned off or is outside of the service area of the SMS network, the attempt to deliver the short message at that time will fail. In this case, the short message will be retained in the SMS network for a later delivery attempt. Thereafter, when the subscriber finally becomes available, e.g., is turned on or has moved into the service area of the SMS network, the relevant portions of the network (e.g., the mobile servicing center (MSC) and the home location register (HLR)) notify the SMSC to initiate delivery of the stored (i.e., previously failed) short messages.
FIG. 6 shows an exemplary structure of a SMS network 500. Although the following example is described using terms and protocols mainly as defined by the North American standard IS-41, it will be apparent to one skilled in the art that the example is applicable to any networks that offer store-and-forward type short message service.
The SMS network 500 typically includes one short message service center (SMSC) 501. The SMSC 501 typically includes a storage subsystem to store short messages that had failed to be delivered. The SMSC 501 typically further includes various interfaces (not shown) to receive short messages originating from various sources and protocols, such as a Voice Mail System (VMS) 508, paging networks using, e.g., Telocator Numeric Paging Protocol (TNPP) 509, devices using the Short Message Peer-to-Peer (SMPP) protocol 510 via TCP/IP, e-mail systems using the Simple Mail Transport Protocol (SMTP) 511, and/or devices using the Telocator Alphanumeric Protocol (TAP) 512. Some of the various sources of the short messages may be gateways to other networks.
The SMSC 501 may further include a gateway/interworking block (not shown) that enables the SMSC 501 to communicate with the rest of the SMS network 500, such as a Home Location Register (HLR) 503 or a Mobile Switching Center (MSC) 505, using the Signaling System No. 7 (SS7) 502. The methods and mechanism of communication in the SMS network 500 are defined by the mobile application part (MAP) layer, which uses the services of the SS7 transaction capabilities application part (TCAP) as the signaling infrastructure of the SMS network 500. The protocol for the signaling is referred to as the IS-41 protocol under the American standard as published by the Telecommunication Industry Association (TIA) or as the GSM MAP under the European standard published by European Telecommunication Standards Institute (ETSI).
The Home Location Register (HLR) 503 includes a database that permanently stores and manages subscriptions and service profiles of users having a subscription to the SMS network 500. Although only one HLR 503 is shown, the SMS network 500 may include two or more HLRs. The SMS network 500 also typically includes several visitor location registers (VLR) 504. A VLR 504 is a database temporarily holding information about visiting subscribers who move into its service area. Thus, a VLR 504 contains information regarding routing information for all subscribers within its service area, and informs the relevant HLR 503 of the availability and routing information regarding its subscribers. The mobile switching center (MSC) 505 obtains subscriber information from the VLR 504 to service visiting subscribers.
The mobile switching center (MSC) 505 performs switching and call control functions, and receives short messages from the SMSC 501 for delivery to the appropriate mobile subscriber 507 (shown, e.g., as a cellular phone handset). It is to be understood that, although only one MSC 505 is shown, the wireless network 500 may include two or more MSCs.
The base station subsystem (BSS) 506 handles the wireless communications, e.g., RF transmission and reception of voice and data traffic, to and from the mobile subscriber 507. The BSS 506 is typically composed mainly of two parts: the base transceiver station (BTS, not shown) which houses the radio transceivers that define a cell and handles the radio-link protocols with the mobile subscriber 507, and the base station controller (BSC, also not shown) which manages the radio resources, and handles radio channel set up, frequency hopping, and handoffs (or handovers as is sometimes referred as). The BSC is the interface between the MSC 505 and the subscriber 507. The subscriber 507, also sometimes referred to as a mobile station (MS), typically consists of mobile equipment (e.g., a cellular phone handset) preferably uniquely identifiable by an identifying number, e.g., mobile identification number (MIN), International mobile subscriber identification (IMSI) and/or electronic serial number (ESN), for the subscriber 507. The mobile equipment may include a storage area, e.g., a flash memory, a ROM, a RAM or the like to hold the unique identifying number within the mobile equipment. In GSM networks, a smart card, typically referred to as a subscriber identity module (SIM) is utilized to store a unique identifying number.
FIG. 7 shows an exemplary flow of a short message through a conventional SMS network. Although FIG. 7 shows only an example of short message delivery to a mobile subscriber, it is to be understood that a mobile subscriber or any other sources may originate a short message. The flow of a mobile subscriber originated short message would involve similar processes as the following mobile subscriber terminated short message example, and would be apparent to one of ordinary skill in the art.
The SMSC 601 receives a short message intended for a subscriber 604 from a source of short message 605 which may be any one or more of the aforementioned sources of short messages, e.g., 508-512 of FIG. 6. Upon receiving a short message, the SMSC 601 sends a request for routing information, i.e., an SMS request (SMSREQ), to the HLR 602. The HLR 602 maintains information regarding the availability of the intended subscriber 604 and the appropriate MSC 603 that services the intended subscriber, and sends the information as routing information 608 back to the SMSC 601. The SMSC 601 forwards the short message to the appropriate MSC 603 using the routing information 608 received from the HLR 602, for example, in accordance with the short message delivery point-to-point (SMDPP) mechanism of IS-41 standard. The MSC 603 queries the VLR (not shown) for subscriber information. The VLR may perform a paging and authentication process, and sends the subscriber information to the MSC 603. The MSC 603, using the information received from the VLR, delivers the short message to the intended subscriber 604, and sends a delivery report 612 to the SMSC 601. The SMSC 601 may send the result of the delivery, i.e., the status report 613, to the source of the short message 605 if requested.
When the attempted delivery of the short message has failed because, for instance, the intended user was out of the service area, or had his or her communication device turned off, the MSC 603 informs the HLR 602 of the failure. The HLR 602 then turns on an SMS notification indicator flag for the subscriber, and the SMSC 601 retains the failed message for a later delivery attempt.
FIG. 8 shows a pending short message delivery process in a conventional short message service network after the mobile subscriber becomes available for delivery of the retained messages. In particular, in FIG. 8, when the subscriber 704 turns his or her handset on or comes within the service area, the subscriber's handset sends a registration signal 709 to the MSC 703. The registration signal 709 may or may not include authentication process.
Upon receiving the registration signal 709, the MSC 703 informs the HLR 702 (or the VLR 711) of the availability of the subscriber 704 by sending a subscriber available signal 708. Because the SMS notification flag for the subscriber is on, the HLR 702 or the VLR 703 sends an SMS notification (SMSNOT) message 705 in case of networks implementing IS-41 standard, or an equivalent notification alerting the fact that the subscriber has become available in networks implemented in accordance with other standards, to the SMSC 701 assigned to service that particular intended subscriber 704.
The SMSC 701 then sends a delivery request 706 to the MSC 703 via, for example, the SMDPP protocol in the IS-41 standard. The MSC 703 finally delivers the short message 710 to the subscriber 704, and sends a message delivered message 707 back to the SMSC 701 to confirm and finalize the delivery of the short message. The SMSC 701 may further send a delivery report to the source of the short message if it was requested.
The Wireless Application Protocol (WAP) attempts to standardize a mechanism for two-way communications. However, WAP requires that a special browser be loaded on the handset, and requires the user to enter into a dedicated ‘browser mode’ in order to interact with 2-way services.
There is a need for a standardized solution allowing short message communications between wireless devices and application servers on the Internet without the need for a specialized browser, while making use of existing communication standards utilized by standard SMSCs, e.g., SMPP.